Generating alternating current



Sept. 28, 1937. w. zlNGG 2,094,141

GENERAT ING ALTERNAT I NG CURRENTS Filed Aug. 1, 1935 ATTORNEYS.

Patented Sept. 28, 1937 UNITED sTATEs PATENT OFFICE GENEBATING ALTERNATING CURRENT Application August 1, 1935, Serial No. 34,174 In Switlerland August 17, 1934 5Claiml.

The present invention relatesto a novel and improved method of and apparatus for generating controlled frequency alternating current to be superposed on a network for transmission to and operation of resonant relays.

Objects and advantages ofthe invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, construction, arrangements, combinations and improvements herein shown and described.

The accompanying drawing, referred to herein and constituting a part hereof, illustrates one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

In the accompanying drawing, there is shown diagrammatically an illustrative form of an apparatus for carrying the method of the present invention into practice. The lay-out is shown for transmitting three control currents of frequencies which differ from one another, although the transmitting apparatus can be constructed for transmitting any desired number of control currents.

The invention provides a method of and apparatus for producing and transmitting control currents of definite frequency for effecting the remote control of resonance relays in which a generator operates at a variable speed and is connected to the network through a switch when a definite frequency has been reached and also which employs a control device actuating at least the net-work-connecting switch of the generator. Preferably, the control device is actuated by the difference of two magnitudes, of which one is a constant magnitude per se and corresponds in its value for the time being to the frequency of the control current to be transmitted, and they (Cl. r11- 312) high degree of reliability and high accuracy with respect to the frequency control of the motor generator group. Furthermore, for a new distribution of the range of control frequencies, the synt chronous motors need not be replaced by others, 5 since the necessary alterations of speed can easily be obtained by interchanging the wheels of the transmission gear. Also synchronous motors are not dependent upon temperature, and comparatively high powers can be produced, so that by 10 rthis means the danger of uncertain operation of 'apparatus may be divided into a motor generator 25 group A, a speed regulating group B, a synchronous motor group C and a controlling group D The motor generating group A comprises a shunt motor I, a generator 2 for alternating cur- 30 rent of medium high frequency, and a generator I for alternating current of low frequency, these I generators being geared to and driven by the shunt motor I. The current generated by the main generator 2 is transmitted to' the distribu- 35 tion network 4 through a solenoid-operated switch 5, while the auxiliary or low frequency generator I delivers its output to a self-starting synchronous motor 6.

'I'he speed regulating apparatus comprises a 40 driving motor I0 having a sub-divided field winding II, either half of which can be placed in circuit for operation of the motor in either direction. Motor III is geared to the rotary contact arm I2 of a variable resistance II through 45 gearing I4, and one of the gears Il is mounted on a shaft which can be slightly rocked and is normally held out of engagement with the other gear by means of a spring il, being Leid ln en- Eagement by means of armature IB which is acted upon by magnet winding I1 receiving its POWer from the conductors I8. A spring I l is provided for resetting the contact arm I! to a definite position each time that the gem i4 56 Yare placed out oi mesh by the action of spring I upon de-energization of winding Il.

The synchronous motor group C comprises a plurality o self-starting synchronous motors 20, 20 and 20,which are connected to a common gear 2| by means of the gearings 2'2, 22' and 22 and one-way clutches 23, 23 and 23". The gearings 22,' 22' and 22" are preferably of diierent i other desired factor.

The controlling device Dcomprises diierential gearing 30, including the sun wheel 3| driven from synchronous motor 8, the sun wheel 32 driven from gear 2| and the planet wheel 33 which is connected to one side of a friction clutch 34 to drive gear 35. Gear 35 is arranged to mesh with gear 36 whenever armature 31 is attracted by magnetic winding 38 against the tension of spring 39. Gear 36 is connected with a gear 40 meshing with gear 4|, which in turn is connected to the contact arm 42. 'Upon release of the armature 3'I, spring 44 returns the contact arm 42 to its normal position, which isi that shown in the drawing.

Contact arm |32 is adapted to contact with switch contacts 45t-and 46, and these contacts are Yconnected to opposite ends of the divided iield winding |I of the regulating motor I3, while v the central point of eld winding |I is connected to the conductor i8. Contact arm d2 is connected through motor Ii to the other conductor it. A

momentary switch tl is closed by the contact arinA 42 upon each movement from one contact it or t6 to the other, and one contact of switch di is connected to one of theconductors It, while the other contact is connected to one end of the magnet winding #33, which has its other end connected to the other conductor i3 for the operation of switch t. A switch (t3, in parallel to switch 47 and actuated by the magnet winding 38, is provided for holding the main switch closed once the contacts of switch t1 have been momentarily brought together.

The generator driving motor is supplied with current from the conductors I3, and current is supplied to these conductors through switch V53 from the direct current mains 5|, switch 53 bei'g' moved to and held in closed position so long las any one of the switches 25, 25' or 2B" is closed. Driving motor I is provided with a field winding 60 supplied with current from conductors I8 through resistance i3, and as4 the position of contact arm I2 is varied, the speed of the driving motor I is accordingly varied, thereby varying the frequency ci the current.. generated by generators and 3.

In the position of rest, the synchronous motors 2t, 2t' and 23" are inoperative, and switch t@ is open. Magnet id is de-energzed and contact arm i2 is held against its stop by spring t3. Contact arm. l2 is similarly held against contact 4t and the main switch ii is open. The driving motor i and the associated generators t and S are also at rest.

tihen it is desired to transmit alternating current of one of the desired frequencies over the network il, one of the y*switclfies 2t, 225' or 2t" is a-,cearai closed, simultaneouslyv closing the switch @3. Current is thereby supplied to one of the motors 2t, 20' or 20", rotating gear 2| and sun gear 32 at a predetermined speed, the speed depending upon which one of the several motors was placed in operation. The closing of switch 53 also supplies current to the magnet windings I1 and 38, connecting motor IIJ with contact arm I2 and connecting the planet wheel 33 with contact arm 42. The closing of switch 50 also supplies currentl to the driving motor I to drive generators 2 and '3, and the current generated by generator 3 operates the self-starting synchronous motor I to rotate sun-wheel 3| reversely to the rotation of sun wheel 32. The rotation of these differential gears c auses planetary gear 33 to revolver until the speed of gears 3| and 32 is equal in opposite directions, maintaining contact arm 42 against contact 45 to supply current to the left halt oi iield winding II, and thereby causing rotation of motor I0 to move the contact arm I2 along resistance I3 to reducethe current ilowing through field winding 60 of motor I, thereby increasing the speed of driving motor I to cause a concomitant increase in the frequency o! the current generated by generators 2 and 3. The operation of motor Ill upon contact arm I2 is relatively slow compared with the speed of operation of contant arm 42. When the speed of motor 8 very slightly exceeds the speed required to drive sun gear 3| at the same rate as sun gear 32, planetary gear 33 is slowly reversely revolved, causing movement of contact arm 42 towards contact 46, and thereby indicating that the driving motor is running at a speed which corresponds to the frequency desired from generator 2. Contact arm 42 causes a momentary closure of switch' 41 energizing holding coil 48 to move switch 5 to circuit closing position where it is held by the current owing to the coil t8 through switch 43. Movement of the contact arm 42 away v of the currents generated by generators 2 and 3.

'I'iiis reduction in frequency causes a corresponding reduction in the speed of rotation of motor Q and causes contact arm 42 to be moved towards and to contact with contact 45, after which the oscillation of contact arm 42 between contacts 46 and 46 continues so long as the switch 25, 26' or 25" is maintained closed. This alternate reversal of the controlling motor I0 causes a corresponding iluctuation of minor magnitude in thev frequency generated by the main generator 2 for transmission over the network to the resonant' relays, and this uctuation is advantageous in that it insures operation of all the relays tuned to that frequency eventhough the tuning of certain o these relays may not be entirely accurate.

By selecting different gear ratios for the gears it, 3|, 35, t6, @30, and Gi, the amount of this uctuatn in speed, and the relative time at which contact arm 32 begins to move, can be accurately predetermined, but the speeds are prei'- erably so selected that contact arm 52 begins to move very slightly before the predetermined desired irequency `has been v attained.

When it is desired to interrupt the transmission of any one of the frequencies, the corresponding switch 25, 25' or 25" is opened, opening switch 50 which in turn opens switch B, magnets I1 and 38 are de-energized, returning contact arms I2 and 42 to their original. position and motors I, 8, and I0 come to rest, thereby restoring all of the parts to their original position and placing the entire apparatus in condition for the transmission of the same or a different frequency.

In place of the synchronous motors 20, 20' and 2li" for producing the different speeds of rotation of sun-wheel 32, a single synchronous motor may be employed supplied with current of predetermined different frequencies as, for instance, from various'selectively operable thermionic vacuum tube generators. v

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. Apparatus for the controlled generation and transmission of alternating current of different frequencies for the operation of resonant relays including in combination an alternating current generator, a variable speed motor driving said generator, means regulating the frequency generated by the generator, means driven proportionally to said generator, means operating at any one of a plurality of fixed speeds, means operated by difference in speed between one of said fixed speeds and said proportionally driven means, means controlling the regulating means by said difference-operated means, 'a switch in circuit with said generator and means controlled by said difference-operated means for closing said switch to supply current to a transmission network.

2. Apparatus for the controlled generation and transmission of alternating current of diiferent frequencies for the operation of resonant relays including in combination an alternating current generator, a shunt wound motor driving said generator, means including a variable resistance in the field windings of the motor for regulating the frequency generated by the generator, means driven proportionally to said generator, means operating at any one of a plurality of fixed speeds, means operated by the difference in speed between .one of said xed speeds and said proportionally driven means, means controlling the variable resistance by vsaid diii'erence-operated means, a switch in circuit with said generator and means controlled by said difference-operated means for closing said switch to supply current to a transmission network.

3. Apparatus for the controlled generation and transmission of alternating current of different frequencies for the operation of resonant relays including in combination an alternating current generator, a variable speed motor driving said generator, means regulating the frequency generated by the generator, means driven proportionally to said generator, means operating at any one of a pluralityof fixed speeds, means operated by the difference in speed between one of said fixed speeds and said proportionally driven means, means including a reversible motor acting on the driving motor for controlling the regulating means by said difference-operated means, a switch in circuitwith said generator and means controlled by said difference-operated means for closing said switch to supply current to a transmission network.

4. Apparatus for the controlled generation and transmission ot alternating current of different frequencies for the operation of resonant relays including in combination an alternating current generator, a variable speed motor driving said generator, means regulating the frequency generated by the generator, means driven proportionally to said generator, means operating at any one of a plurality of iixed speeds, means operatedby the difference in speed between one of said fixed speeds and said proportionally driven means, means `controlling the regulating means by said difference-operated means, a switch in circuit with said generator, means controlled by said difference-operated means for closing said switch to supply current to a transmission network, and means for resetting all of the elements to a normal position.

5. Apparatus for the controlled generation and transmission of alternating current of different frequencies for the operation of resonant relays including in combination an alternating current generator, a second alternating current generator driven proportionally thereto, a variable speed driving motor for said generators, a regulating resistance in the motor circuit, a synchronous motor driven by said second generator, a plurality of synchronous motors for producing a plurality of constant speeds, individual one-way clutches through which said motors may drive, means for controlling the regulating resistance and including diiferential gearing having one sun gear driven proportionally to the speed of the synchronous motor and having its other sun gear alternatively coupled to one of the constant speed motors by one of said one-way clutches, and with its planetary pinion connected to operate the regulating means by the difference between said speeds, a switch connecting the first generator to a transmission line, and means controlled by the planetary pinion for closing said switch.

WERNER ZINGG. 

